Doctor-operating mechanism for calendering machines



J. A. FROSSARD ET AL DOCTOR OPERATING MECHANISM FOR CALENDERING MACHINES Filed April 8, 1926 2 Sheets-Sheet 1 37 i O I 4 wr v 47 Znwrziars:

a i may 1644,91? 1927' J. A. FRQSSARD ET AL DOCTOR OPE RATING MECHANISM FOR CALENDERING MACHINES Filed April 1926 2 Sheets-Sheet 2 Illll al 1.

J i l 75hr? .71. iraazsarc 6590/7 e zamaareax Patented Oct. 11, 1927.

UNITED STATES PATIENT oF IcE.

JOHN A. FROSSABD, OF PEPPERELL, AND GEGRGE LAMOUREUX, OF WORCESTER,

MASSACHUSETTS.

DOCTOKOPERATING MECHANISM FOR CALENDERING- MACHINES. A

Application filed April 8, 1926. Serial No. 100,688.

Our invention relates to calenderin machines, as employed in paper making, an has for its object to provide animproved mechanism for operating the doctors, or

a scrapers that are customarily employed in connection with the calendering rolls.

In the operation of a calendering machine, it is necessary to apply the doctors to the rolls only at intervals, as when threading 1c the paper through the stack of rolls, or when it is desired to clean the surface of the rolls while making a run. According to our invention, we provide an improved mechanism for simultaneously operating all the doctors for a stack of rolls so as to :1 ply a predetermined amount of pressure uni ormly to all of the rolls, or to simultaneously release all of the doctors from engagement with the? rolls. Our invention contemplates the provision of a separate power unit or operating device for each doctor and means whereby all of these devices will be simultaneously connected to a common source of power, either automatically, at predetermined intervals, or at the will of an operator.

Our invention further contemplates an improved doctor so constructed that it will be maintained by the force of gravity out of engagement with its associated calendering roll, so that the only way in which the doctor can be applied is by connection to the source of power, or manually. Our improved construction also permits any doctor to be disconnected from its erating device for manual operation, in ependently of the other doctors in the roll stack. The above and other advantageous features of our invention will hereinafter more fully appear, reference being had to the accompanying drawings in which Fig. 1 is a view in side elevation of a stack of rolls of a calendaring machine with our doctor mechanism applied thereto.

Fig. 2 is a view, partiall in section and partially in side elevation, s owing one doctgil and its operating device on an enlarged s e.

Fig. 3 is a plan view of the parts shown in Fig. 2..

Fig. 4 is an end view of the parts shown in Fig. 2.

Fig. 5 is-a detailed view of the controlling valve for the doctor mechanism.

Like reference characters refer to like parts in the diiierent figures. 1

Refer first to Fig. 1, the calendaring and the doctors 6 may machine comprises a suitable frame 1 for rotatably supporting a set of rolls 2, one above the other, an endles web of paper 3 being indicated in dotted lines as entering the machine at the top and leaving at the bottom. The frame 1 rovides vertical guideways 4 which carry a justably mounted mechanism in detail. As best shown in Fig.

3, each bracket 5 provides an arm 7 having an opening 8 at its end for receiving one of the projecting trunnions 9 of a cyllnder 10 which extends all the way across the machine parallel to the associated roll 2. The trunnion 9 is-received in a bushing 11, closing one end of the-cylinder 10, and is secured by means of one or more set screws 12, thereby permitting longitudinal adjustment of the cylinder 10 between the end frames 1.

As best shown in Fig. 2, an angle bar 13 is supported by the cyhnder 10 and this bar 13 carries a doctor 6, here shown in the form of a plate, or sheet of metal. The doctor 6 is clamped between plates 14 which are in turn secured to the angle bar 13 by a number of spaced fingers 15. The fingers 15 are secured to the angle bar 13 by bolts 16 passing through slots 17 whereby the fingers 15 be adjusted on the bar 13. It is evident that the fingers 15 are adapted to yield somewhat in response to pressure to permit the doctor 6 to adjust itself to the roll 2, as will be hereinafter described.

The angle bar 13 is secured to thecylinder 10 by means of bolts 18 and 19 extending through the cylinder at ri ht angles to each other, and since the ang e bar 13, with the doctor 6, is mounted eccentrically with res eat to the axis of the trunnions 9, it is evi ent that in the absence of any other force acting on the cylinder 10, each doctor 6 will tend to hang in a position in which it is out of engagement with its associated,

roll 2, as shown in Fig. 1. Each angle bar 13 is capable of adgustment on the periphery of its cylinder 10 by reason of the fact that the bolts 18 and 19 pass through slots 20 in both legs 13 and 13 of the bar 13, so that'the bar 13 may be shifted bodily when the nuts 21 on the bolts 18 and 19 are loosened. In order to permit of delicate adjustment of the bar 13, studs 22 are rovided at intervals between the through bolts 19 on the leg 13 of the bar 13, which studs 22 bear on the peripher of the cylinder 10 and provide means w ereby the leg 13 of the bar may be forced away from the cylinder 10. The bar 13 can be locked in position after such an adjustment by means of lock nuts 23 on the studs 22.

An operating handle 24 is secured to one trunnion 9 of each cylinder 10 by means of a set screw .25, and the cylinder 10, together with the doctor construction, can be turned by means of this handle 24 to bring the doctor 6 into engagement with the periphcry of its associated roll 2. The handle 24 is provided at its free end with a latch 26 pivoted at 27, and this latch 26 is normally eld in position between a pair of ears 28 on a collar 29 by means of a spring 30, see Fig. 3. The collar 29 is carried on a rod 31 slidably mounted in a bracket 32, and one end of this rod 31 extends into a cylinder 33, where it is provided with a piston 34. The cylinder 33 is ada ted to be connected to a suitable source 0 pressure by means of a pipe 35, and it is evident from Fig. 1, that the cylinders 33 of all of the doctor gperating units are similarly connected.

onsequently, when a pressure medium is admitted to any cylinder 33, the piston 34 will be moved to the osition shown in Fig. 2, and thereby turn t e handle 24 to maintain the doctor blade 6 in engagement with the roll 2.

If, however, the pressure in a cylinder 33 should be released, it is evident that the unbalanced weight of the doctor 6 and the angle bar 13 will cause the cylinder 10 to turn on its trunnions in a clockwise direction, so that the doctor blade will fall away from the cylinder, as shown in Fig. 1. As

shown in 4, the operating handle 24 is constrained to move with the piston rod 31, but should it be desired to turn the handle 24 independently of the piston rod 31, the latch 26 may be disengaged from the cars 28 by depressing the same against the spring 30, whereu on the handle 24 ma be turned freely; is detachable latci connection permits any doctor 6 to be manually operated independently of the other doctors.

As clearly shown in Fig. 1, the pipes 35 leading'from the various doctor operating cylinders 33 all lead to a common control valve 36 which is ada ted to admit a pressure medium to all 0 the pipes 35 from a suitable pressure source, not shown. The

valve 36 is illustrated in detail in Fig. 5, and provides-an inlet passage 37, an exhaust passage 38 and an outlet passage 39. The outlet and exhaust passages 38 and 39 open into a common chamber 40, and this chamber is normally shut oil from an inlet chamber 41 by means of a spring pressed valve 42 engaging a seat 43. The exhaust passage 38 is adapted to be closed by a disk valve 44 mounted on a stem 45 which extends outside the valve and is connected to an operating lever 46. The stem 45 also extends inside the chamber 40, so that when the valve 44 is moved to close the exhaust opening 38, the stem 45 engages the valve 42 and opens it to admit the pressure medium to the chamber 40. Normally, the exhaust port38 is open so that all of the cylinders 33 are open to the atmosphere and all of the doctors are out of engagement with their corresponding rolls 2, as shown in Fig. 1. is turned to close the exhaust valve 44, opening of the inlet valve 42 admits the pressure medium to all of the cylinders 33 simultaneously, so that all of the doctors 6 are immediately applied to the rolls 2. The lever 46 can be operated manually, or can be operated automaticall by the arrangement shown in Fig. 1, which will now be described.

The lever 46 is provided at its end with a roller 47 which is maintained in engagement with the peri hery of a cam disk 48 by a spring 46. T e cam disk 48 is mounted on a shaft 49 which also carries a ratchet wheel 50. The ratchet wheel 50 is adapted to be turned by a finger 51 pivotally mounted at one end on an eccentric disk 52 carried on the shaft 53 of the bottom roll 2. It is evident that each complete revolution of the bottom roll 2 will cause the finger 51 to advance the ratchet wheel 50 through the space of one tooth, the wheel 50 being locked by a pawl 54. As the cam disk 48 rotates with the ratchet wheel 50 with a slow intermittent movement, a cam projection 55 will finally engage the roller 47 on the lever 46, thereby turning the lever 46 about its ivot 56 to close the exhaust valve 44 and a mitting the presure medium to all of the cylinders 33.

When this occurs, all of the doctors 6 will be applied to the rolls 2 and the doctors will engage the rolls only aslong as the lever 46 1s acted upon by the cam projection 55. As the roller 47 passes ofi the cam rejection 55, the lever 46 will be turned by t e spring 46 in the opposite directiop to open the exhaust valve 44 and close the inlet valve 42, whereupon pressure will be simultaneously exhausted from all of the cylinders. 33 and the doctors 6 will fall away from the rolls 2. With this arrangement, the doctors are automaticall applied to the rolls at predetermine intervals during the operation of When, however, the lever 46 the caleiidering machine, and it is obvious that the frequency and duration of the doctors application can be varied as desired.

The doctor 6" which engagesthe bottom roll of the stack is reversed so that it rests by gravity in continuous engagement with this roll, even when the pressure is exhausted from the'cylinders 33. Therefore, when the pressure is applied, as previously described, the doctor 6" will be applied with an increased pressure.

lVe claim:

1. Ina doctor mechanism for calendering machines, the combination with a pluralityof calendering rolls. and a plurality of pivotally mounted doctors for said rolls, of levers connected to said doctors, individual power units for severally operating said levers, and controlling means for rendering all the power units operative or inoperative to apply the doctors.

2. In a doctor mechanism for calendering machines, the combination with a plurality of calendering rolls, and a lurality of doctors for said rolls, of individual power units for severally operating said doctors, and automatic means for simultaneously putting said power units in operation.

3. In a doctor mechanism for calendaring machines, the combination with a plurality of calendering rolls and aplurality of pivotally mounted doctors for said rolls, of levers operatively connected to said doctors, individual power units, for severally operating said levers, and means for detaching said levers from said ower units, whereby to operate any indivi ual doctor by hand.

4. In a doctor mechanism for calenderin machines, acylinder horizontally journalle in end frames, an angle bar the inside faces of'which are held tangent to said c linder,

and a doctor blade carried by said ar, the

center of gravity of said structure being between the doctor blade and the axis of rotation of the cylinder, so that the blade tends by gravity to move downward.

5. In a doctor mechanism for calenderin machines, a cylinder horizontally journalle in end frames, an angle bar carrying a doctor blade, the inside faces of said angle bar tors for said rolls, of indivi ual power units for severally operating said doctors, coni trolling means for ren ring all the ower units operative or inoperative t0 app y the doctors, and means driven by said calenderingmachine to automatically actuate said controlling means.

7. In a doctor mechanism for calendering machines, the combination with-a plurality of calendering rolls, and a plurality of doctors for said rolls, of individual power units for severally operating said doctors, controlling means for rendering all the ower units operative or inoperative to a p y the doctors, and means for automatica actuatmg said controlling means after said rolls have made a predetermined number of revolutions.

8. In a doctor mechanism for calendering machines, the combination with a plurality of calendering rolls, and a plurality of doctors for said rolls, of means for applying all of said doctors at once, and automatic means for rendering said first named means operative at regular intervals, said automatic means comprising a member controlled from one of the calendering roll shafts.

9. In a doctor mechanism for calendering machines the combination with a plurality of calendering rolls, and a plurality of pivotally mounted doctors for said rolls, of levers connected to said doctors, individual pressure controlled units for severally operating said levers, and a single control valve for rendering all the ressure units operative or inoperative to app y the doctors.

JOHN A. FROSSARD.

GEORGE LAMOUREUX. 

